hash: 64 bit variants.

[ccan] / ccan / hash / test / run.c

diff --git a/ccan/hash/test/run.c b/ccan/hash/test/run.c
index 2aeec42d94a06f7543ec1560323a67d902ed4649..31d4ecb59a6ab7c82776f0576994d06b28c79450 100644 (file)
--- a/ccan/hash/test/run.c
+++ b/ccan/hash/test/run.c
@@ -17,7 +17,7 @@ int main(int argc, char *argv[])
        for (i = 0; i < ARRAY_WORDS; i++)
                array[i] = i;
 
-       plan_tests(22);
+       plan_tests(39);
        /* Hash should be the same, indep of memory alignment. */
        val = hash(array, sizeof(array), 0);
        for (i = 0; i < sizeof(uint32_t); i++) {
@@ -51,6 +51,31 @@ int main(int argc, char *argv[])
                diag("Byte %i, range %u-%u", i, lowest, highest);
        }
 
+       /* Hash of random values should have random distribution:
+        * check one byte at a time. */
+       for (i = 0; i < sizeof(uint64_t); i++) {
+               unsigned int lowest = -1U, highest = 0;
+
+               memset(results, 0, sizeof(results));
+
+               for (j = 0; j < 256000; j++) {
+                       for (k = 0; k < ARRAY_WORDS; k++)
+                               array[k] = random();
+                       results[(hash64(array, sizeof(array), 0) >> i*8)&0xFF]++;
+               }
+
+               for (j = 0; j < 256; j++) {
+                       if (results[j] < lowest)
+                               lowest = results[j];
+                       if (results[j] > highest)
+                               highest = results[j];
+               }
+               /* Expect within 20% */
+               ok(lowest > 800, "Byte %i lowest %i", i, lowest);
+               ok(highest < 1200, "Byte %i highest %i", i, highest);
+               diag("Byte %i, range %u-%u", i, lowest, highest);
+       }
+
        /* Hash of pointer values should also have random distribution. */
        for (i = 0; i < sizeof(uint32_t); i++) {
                unsigned int lowest = -1U, highest = 0;
@@ -75,6 +100,13 @@ int main(int argc, char *argv[])
                diag("hash_pointer byte %i, range %u-%u", i, lowest, highest);
        }
 
+       if (sizeof(long) == sizeof(uint32_t))
+               ok1(hashl(array, sizeof(array), 0)
+                   == hash(array, sizeof(array), 0));
+       else
+               ok1(hashl(array, sizeof(array), 0)
+                   == hash64(array, sizeof(array), 0));
+
        /* String hash: weak, so only test bottom byte */
        for (i = 0; i < 1; i++) {
                unsigned int num = 0, cursor, lowest = -1U, highest = 0;